Price of book in 1938 = $ 0.10
Price of book in 2011 = $ 2,161,000
Number of years over 1938-2011 = 2011 - 1938 = 73
Annual increase in the price = [tex]((\frac{\text{Price of book in 2011}}{\text{Price of book in 1938}}) ^ \frac{1}{\text{Number of years}} - 1 ) * 100[/tex]
⇒ Annual increase in the price = [tex]((\frac{2,161,000}{0.1}) ^ \frac{1}{73} - 1 ) * 100[/tex]
⇒ Annual increase in the price = (1.260302283 - 1 ) × 100
⇒ Annual increase in the price = 0.260302283 × 100
⇒ Annual increase in the price = 26.0302283 %
⇒ Annual increase in the price = 26%
Hence, the comic book price increased by 26% annually